X-ray apparatus



Feb. 28, 1967 c. R. GRIFFITH 3,306,605

X-RAY APPARATUS Filed May 12, 1965 2 SheetsSheet l WITNESSES INVENTOR flwvafl Q Charles R. Griffith BY x2 1957 v c. R. GRIFFITH 3,306,605

X-RAY APPARATUS Filed May 12, 1965 2 Sheets-Sheet 2 MAX-- (A) TOP-EDGE WOULD HIT THE FLOOR I F|G.3-

5 P (B) LIMIT SWITCH OPERATION 6 (FIGS- I82) 0. O (c) LIMIT SWITCH OPERATION I I I I I I I O IO TILT ANGkEDOF TABLE SWITCH ROTARY POSITION TILT RETURN 34 \lilf i so 53 F I64. W 1\ 38 4 v 55 I TILT-MOTOR A: Q 4? I n 0.0. F 39 SOURCE 6O i 8 I TOP-EXTENSION 50 g MOTOR 45- 42 49 46 41 V58 7 T T 59 u EXTEND RETRACT O/'=\ g/ Q OFF FIG.5.

3,306,605 X-RAY APPARATUS Charles R. Griffith, Baltimore, Md., assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed May 12, 1965, Ser. No. 455,281 3 Claims. (Cl. 269323) The present invention relates to X-ray apparatus, and more particularly to power-driven tiltable X-ray tables having extendable tops.

Many present-day X-ray tables, in addition to being tiltable, also include a top which is extendable beyond one or the other edge of the table. The table also includes power actuator means for effecting the tilting of the table and the extension of the table top. Since the top may extend over an end of the table, it becomes necessary to provide actuator-operation-limiting means to prevent an extended table top from striking adjacent fixed objects such as the floor or ceiling, for example, during certain degrees of table tilting in accord wit-h the degree of extension of the table top.

Such actuator-opeartion-limiting means heretofore proposed have been characterized by a relatively high degree of complexity and have been less than entirely satisfactory with respect to the characteristics of the limits imposed on the power actuation of the several motions involved.

In view of the foregoing remarks it becomes a prime object of the present invention to provide an improved motion-limiting system in an extendable-top tiltable X-ray table, which is relatively simple in construction and capable of affording a greater degree of freedom for the several movements involved in such table.

In accord with the general features of the invention, there is embodied in an extendable-top tiltable X-ray table having power actuator means for tilting the table and extending the table top, a motion-integrating means which is constructed and arranged to control operation of an actuator-operation-limiting means according to both the angular position of the table and the degree of extension of the table top.

Other objects, features, and advantages of the invention will become apparent from the following detailed description thereof when taken in connection with the accompanying drawings, in which:

FIGURE 1 is a front elevation view, partly in outline nited States Patent and partly in section, of an exemplified embodiment of the invention as shown schematically;

FIG. 2 is a similar view showing the X-ray table and mechanism illustrated in FIG. 1 in a different angular attitude;

. FIG. 3 sets forth curves of operation of the extendabletop tiltable X-ray table as embodying the motion-limiting system of the present invention;

FIG. 4 is a circuit diagram of an exemplified control system for the power actuator means of such an X-ray table embodying the invention; and

FIG. 5 is a diagrammatic representation of a modification of the motion-limiting mechanism of FIGS. 1 and 2.

Referring to FIG. 1, in the illustrative embodiment of the invention as shown therein schematically, there is an X-ray table 1, shown in partial cutaway, which is supported on a pedestal means 2 and is capable of being tilted to difierent angular attitudes about a horizontal tilt axis 3 through the medium of a tilt motor 4 which drives a segmental gear 5 suitably connected to the body of the table for effecting such tilting movement. The table also comprises a top 6 which is extendable relative to the table body through the medium such as a rack 7 extending along the table top and gear-driven by a topextension motor 8. Guide rollers 9 are also included for 3,306,605 Patented Feb. 28, 1967 directing such top-extension movement relative to the table body. The table-tilt motor 4 and the top-extension motor 8 together constitute a power actuator means which operates to tilt the table and to extend the table top.

Referring to FIGS. 1 and 2, the table 1 embodies a novel actuator-operation-limiting means, including a limit switch 12 and a motion-integrating means constructed and arranged to control operation of the actuator-operationlimiting means according to both the angular position of the table 1 and the degree of extension of the table top 6. In the exemplified construction shown in FIGS. 1 and 2, this latter means comprises a rotary member 14 which is turned about the tile axis 3 of the table on a shaft 15 as well as by extension movement of the table top 6 through the medium of gear teeth 16 on the outer periphery of such member 14 which mesh with the teeth of the rack 7 on the extendable table top; and a gravity-oriented member in the form of a pendulum 18 which includes an abutment 20 for engagement with the limit switch 12 to operate such switch when called for according to the cumulative travel thereof as imparted by the rotary member 14 on which such switch is mounted.

Referring to FIG. 3 the curve A represents the topextension and table-tilt positions at which the table-top would hit the floor if left free to do so, and therefore this curve also represents the maximum allowable ideal limit to the relative table-tilt and top-extension travel limit positions. The motion-limit means-construction of FIGS. 1 and 2, when considered that the limit switch 12 when operated by the abutment 20 on the pendulum member 18 ineifect-uates the power-actuator means, provides the straight-line operating characteristics represented by the curve B in FIG. 3, since the arcuate travel of the limit switch 12 fixed to member 14 is directly proportional cumulatively both to the angle of tilt of the X-ray table and the degree of extension of the table top. In the arrangement of FIGS. 1 and 2, since it is desirable that the limit switch 12 permits as much freedom as possible for table top extension and table tilting, the arrangement shown provides for full arcuate travel of the limit switch 12 by full extension of the table top in the horizontal position of the table to a position such as 30 away from the switch operator abutment 20 and which corresponds to the angular position of the table in which a fully extended table top would not strike the floor in the absence of any limit means.

In behalf of further extending the permissible travel of the table 1 and the top 6, the arrangement shown in FIG. 5 provides for altering the relationship between the effective travel of the limit switch 12 and extension travel of the table top to obtain optimum limit operation'characteristics. In the exemplified arrangement this is arrived at by arranging the abutment 20 on the pendulum 18 in an attitude which requires radial movement of the limit switch 12 for actuation by such abutment, and providing for such radial movement according to the angular attitude of the rotary member 14 relative to such pendulum. Such control-member-motion-modifying means as a cam-and-follower arrangement can take the form, as illustrated, of a curved guide rod 22 supported at its opposite ends at 23 and 24 on the rotary member 14 to turn therewith. The guide rod 22 passes through an accommodating opening 26 in the limit switch 12 which is mounted for radialwise sliding movement. By virtue of this arrangement, the degree of radial travel of the limit switch 12 required to reach engagement with the abutment 20 will vary according to the angular position of the table 1 as represented by the rotary member 14, and closure of the limit switch 12 thereby is made to follow the ideal limit operation curve C in FIGURE 3. Thus, limiting of the several motions of the table 1 including its extendable top 6 is enabled without compromising permissive movements.

The showing in FIG. also includes a gear train 28 interposed between the rotary member 14 and the rack 7 affiliated with the extendable table top 6 to enable the size of such rotary member to be kept within practical limits commensurate with the relative degrees of travel required.

Where the travel-motion-control member is in the form of a limit switch 12 commensurate with power actuator means in the form of the several electric motors 4 and 8 as exemplified herein, as is the usual form, such limit switch 12 may be embodied in a motor control circuit such as shown in FIG. 4 and which, for sake of simplicity, presumes operation of such motors from a DC. source, although frequently such motors may in fact be operated from A.C. source. It will be understood, however, that the concepts may readily be transposed into such alternating current system.

In the exemplified control circuit of FIG. 4, the table tilt motor 4 may be operated to tilt the table by actuation of an operators control switch to TILT position to complete a motor-energizing circuit from the DC. source via the line leads 32 and 33, pairs of contacts 34, 35 and 36, 37 of such operators control switch, motor input leads 38 and 39, and a relay-operated normally-closed limit switch 40 in the motor lead 39. Such an operation of the table tilt motor 4 becomes terminated either by return of the operators control switch 30 to its QFF position in which it is shown in the drawing or by the opening of the limit switch 40 as will be described. Separately or simultaneously an operators top-extension control switch 42 may be operated to its EXTEND position to operate the top-extension motor 8 for extension of the table top via an energizing circuit for such motor which includes the line leads 32 and 33, pairs of contacts 44, 45 and 46, 47 of such operators top-extension control switch, motor leads 48 and 49, and a limit switch 50 in series with motor lead 48. Termination of such top-extension motor operation becomes effected either by return of the operators switch 42 to its OFF position in which it is shown in the drawing or by opening of the limit switch 50.

Return movement of the table may be effected by reverse operation of the tilt motor 4 which may be effected by actuation of the operators switch 30 to a RETURN position which establishes by way of pairs of contacts 52, 53 and 54, 55 a reversal in connection of the motor leads 38 and 39 to the source lines 32 and 33. Similarly, retractive movement of the table top may be effected by reverse operation of the top-extension motor 8 through actuation of the operators switch 42 to a RETRACT position which establishes via pairs of contacts 56, 57 and 58, 59 connection of the motor leads 48 and 49 to the line leads 32 and 33.

In the arrangement of FIG. 4, both limit switches 40 and 50 in the table tilt motor circuit and in the top extension-motor circuit, respectively, are operated by a common relay solenoid 60 which in turn is controlled by the limit switch 12 of either the FIG. 5 showing or the FIGS. 1 and 2 showing. By reference to the circuit of FIG. 4, it will be seen that so long as the limit switches 40 and 50 are closed, the table top 6 may be extended and the table may be tilted separately or simultaneously as desired. When the two limit switches 40 and 50 are open as the result of closure of the limit switch 12 on the rotary member 14, which occurs when striking of the table top with such as the floor is imminent, closure of the two limit switches 40 and 50 in the forward-operation supply circuits to the motors is effected during reverse operation of one or both of such motors through establishment of the reverse-operation motor circuit or circuits which are constructed and arranged to exclude such reverse motor operation being the result of suitable operation of the operators control switch or switches 30 and 42. This then makes it possible to again forwardly drive one or the other of the motors 4 and 8 to further increase the tilt of the table or to increase the degree of extension of the table top up to the point when the limit switches 40 and 50 again are opened by virtue of closure of the limit switch 12 on the rotary member 14.

It is also possible in the control circuit of FIG. 4, for example, to fully extend the table top 6 while the table 1 is in such as a horizontal position, and then call for a complete tilting of the table 1 to a vertical position while the operators control switch 30 is held in its TILT position and the other operators control switch 42 is held in its RETRACT position. Under these circumstances if the rate of tilting of the table body 1a tends to override the rate of retraction of the table top 6 so that the limit switch 40 becomes opened and the forward operation of the table tilt motor 4 ceases, such will exist only momentarily until the reverse operation of the top extension motor 8 effects sufiicient retraction to cause the rotary member 14 of FIGS. 1, 2 or 5 to again close its switch 12 with resultant reclosure of the limit switch 40 and thereby automatically permit continued forward operation of the table tilt motor 4. Such start-stop operation of the table tilt motor 4 may continue so long as the operators switch 30 remains in its TILT position and the operators switch 42 remains in its RETRACT position, up to the point where the table assumes its vertical position, whereupon, in accord with the usual procedure, other limit switch means (not shown) will then inetfectuate the several motors involved. Conversely, a similar action may be obtained by holding the op-erators switch 30 in RETURN position to establish a reverse operation of the table tilt motor 4 independently of the limit switch 40, while holding the operators switch 42 in EXTEND position. Under this selected mode of operation the table 1 will return to horizontal position by virtue of forward operation of the top extension motor 4 while operation of the topextension motor is automatically controlled by the limit switch 50 according to whether or not the extension of the table top tends to over-travel the return travel of the table.

From the foregoing description, it will be apparent that by virtue of a motion limit control system of the present invention embodied in an extendable-top tiltable X-ray table, a system is provided which is enhanced by virtue of its inherent simplicity as well as table-motionaccommodating freedom. It will also be apparent that the principles embodied in the illustrative embodiment of the invention described-herein may apply by suitable accommodation, to table motion limit control relative to tilting of the table in one or both directions, extension of the table top in one or both directions, and to operation relative to a fixed proximate object rather than the floor, such as the ceiling or other subject. Such accommodation may involve, for example, addition of other limit switches to the rotary member of FIGS. 1 and 5, and/ or addition of other rotary members, etc.

While I have described above the principles of my invention in connection with specific illustrative embodiments, it is to be clearly understood that this description is made by way of example and not necessarily as a limitation of the scope of my invention as set forth in the objects thereof and in the accompanying claims.

I claim as my invention:

1. An X-ray table mounted on a floor comprising a normally-horizontal normally-retracted top port-ion selectably advancable and retractable in separate top-tilting and straight-line top-extending modes of movement, either mode of movement during advancement being capable of causing the end of such top portion to strike the floor at certain degrees of advancement thereof in the other mode; reversible power actuator means operable to effect advancing and retracting movement of said p p tion Selectively and in either mode selectively;

and control means for said power actuator means, including operators control means and means cognizant of the degree of advancement of said top portion in both modes, operable to efiect advancing movement of said top portion in either mode of such movement, selectively, within a range limited to bringing the aforesaid end of the top portion to positions of non-contacting adjacency to the floor, and to effect retracting movement of said top portion in either mode of such movement, selectively.

2. In a table having a top tiltable about a horizontal tilt axis extending transversely with respect thereto and being translatable by rectilinear movement in a direction normal to the direction of said tilt axis, apparatus comprising two power actuators operable forwardly to extend and to tilt the table top, respectively, and operable reversely to retract and return the table top, respectively, operators control means for controlling operation of said two power actuators, actuator-operation-limiting means, and motion-integrating means controlling operation of said actuator-operation-limiting means according to both the degree of tilt and the degree of extension of the table top, the aforesaid means being so constructed and arranged that extension and tilting of the table top may independently be actuated forwardly and reversely separately selectable degrees within limits determined by both the degree of table top extension and the degree of table top tilt.

3. The combination as set forth in claim 2, further distinguished in that said actuator-operation-limiting means comprises a limit switch means operable to ineffectuate the several actuators and in that said motionintegrating means comprises a rotary member which carries said limit switch means in a vertical plane and is turned cumulatively both by table top tilting and table top translation, and a pendulum member for operation of said limit switch means upon attainment of a certain degree of such cumulative turning movement.

References Cited by the Examiner UNITED STATES PATENTS 2,172,941 9/1939 Manning et al 269-325 2,534,623 12/1950 Pitts et al. 269-323 2,680,046 6/1954 Stave 269-323 2,692,173 10/ 1954 Lowitzsch 269-323 2,816,806 12/ 1957 Zaalberg 269-323 2,958,565 11/1960 Dodson 269-325 3,131,301 4/1964 Barrett et al. 269-323 X FRANK B. SHERRY, Primary Examiner.

FRANCIS K. ZUGEL, Examiner.

G. O. FINCH, Assistant Examiner. 

1. AN X-RAY TABLE MOUNTED ON A FLOOR COMPRISING A NORMALLY-HORIZONTAL NORMALLY-RETRACTED TOP PORTION SELECTABLY ADVANCABLE AND RETRACTABLE IN SEPARATE TOP-TILTING AND STRAIGHT-LINE TOP-EXTENDING MODES OF MOVEMENT, EITHER MODE OF MOVEMENT DURING ADVANCEMENT BEING CAPABLE OF CAUSING THE END OF SUCH TOP PORTION TO STRIKE THE FLOOR AT CERTAIN DEGREES OF ADVANCEMENT THEREOF IN THE OTHER MODE; REVERSIBLE POWER ACTUATOR MEANS OPERABLE TO EFFECT ADVANCING AND RETRACTING MOVEMENT OF SAID TOP PORTION SELECTIVELY AND IN EITHER MODE SELECTIVELY; AND CONTROL MEANS FOR SAID POWER ACTUATOR MEANS, INCLUDING OPERATOR''S CONTROL MEANS AND MEANS COGNIZANT OF THE DEGREE OF ADVANCEMENT OF SAID TOP PORTION IN BOTH MODES, OPERABLE TO EFFECT ADVANCING MOVEMENT OF SAID TOP PORTION IN EITHER MODE OF SUCH MOVEMENT, SELECTIVELY, WITHIN A RANGE LIMITED TO BRINGING THE AFORESAID END OF THE TOP PORTION TO POSITIONS OF NON-CONTACTING ADJACENCY TO THE FLOOR, AND TO EFFECT RETRACTING MOVEMENT OF SAID TOP PORTION IN EITHER MODE OF SUCH MOVEMENT, SELECTIVELY. 